Date: Thu, 21 Jul 2005 03:22:44 EDT
Reply-To: THX0001@AOL.COM
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: George Goff <THX0001@AOL.COM>
Subject: Re: Heli-Coil an Engine Oil Drain?
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Boy, Barry, you've served up a lot to chew on here, but I'll try.
<< Any rate, I've been told that to replace the helicoil with the next size
up is the way to go. I'm nervous about doing this because:
*** Then you have the hassle of finding or machining a drain plug to not only
fit the new thread but also fit within the well around the drain plug hole,
not to mention finding or fabricating a copper washer to fit. Instead of an
oversized HeliCoil, I would be looking for a threaded insert which would be
larger on the OD than the existing HeliCoil hole and have the same thread as the
stock drain plug on the ID. ***
A) Never installed a heli-coil before *** Don't let that bother you; just be
cool and plan your moves.***
B) I'm concerned bout drilling the case by hand and having to keep a hand
drill square to the case so I don't get a cock-eyed hole
*** That's not much of a problem because once a pilot hole is established in
any material it is damned hard to change its path with a twist drill. The
real problem is finding a hand held drill motor which will spin slowly enough for
the size drill you will need to use. Also, slowly enough that you can
prevent the drill from self-feeding.***
C) Concerned about drilling too deep!
*** Be prudent and see above.***
D) How do I keep the drill chips from getting into the engine and slowly
machining my newish powerplant apart?
*** The cuttings are aluminum and the oil strainer should prevent any minor
chip from clogging an oil way. A properly sharpened twist drill run at the
correct speed for its size and for the material being drilled, and with a dab of
aluminum cutting fluid, will produce two long cuttings which will spiral out
of the drill through the flutes. If the aluminum has any tendency to produce
chips, which it shouldn't, you could pressurize the crankcase and drill it dry.
Just make sure to wear some tight fitting goggles. Another dodge which is
used to gather cuttings is to fill the flutes of the drill with grease, drill a
little at a time cleaning and renewing the chipped filled grease after each
step. A Canadian or Gomer Pyle would cork the hole, fill the crankcase to the
brim with Marvel Mystery Oil then drill away.***
. . . . . .
(At this point I think it'd be easier and safer to install a "molly bolt" . .
.
***This won't work very well because the oil will seep around the hole in the
rubber washer. There is something called a well nut. It is basically a
rubber bushing with a captive nut on one end. A screw goes through the bushing
and as it is tightened the well nut expands. There are also test plugs for
piping systems which are very similar to well nuts. And, I am told for I have
never seen one, there are repair oil plugs which are similar to well nuts.
Perhaps you can track one down.***
George
